Execute JavaScript

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already flag destructiveHint=true, openWorldHint=true, and readOnlyHint=false, so the description is not the sole safety signal. It adds value by explaining that results are returned and that both expressions and return-based statements work, but it does not elaborate on side-effect risks of arbitrary JavaScript.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short, front-loaded sentences with no filler. The first sentence states the core behavior; the second and third add return semantics and helper availability. Minor redundancy with the schema's code description keeps it from a 5.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description plus schema covers how to provide code, how to choose a tab, and helper availability, which is enough to invoke the tool. No output schema exists, but the return mechanics are described. It does not address error/async behavior or the scope of side effects, though annotations carry part of that burden.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% for both code and tab_id, so the baseline is already strong. The description goes beyond the schema by naming the available helper library A and its methods (A.all, A.one, A.click, etc.), which materially helps an agent construct valid code.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The opening sentence names a specific action and resource: 'Run JavaScript in a tab and return the result.' This clearly distinguishes it from sibling tools such as get_page_content and query_elements, and the following sentences clarify evaluation semantics.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives no explicit guidance about when to choose execute_javascript over sibling tools, no exclusions, and no prerequisites. The helper-library note and return behaviors are operational details, not selection guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.